----- Original Message ----- From: J. C. O'Connell Subject: RE: Exposure
> For example: > > Say his lens is consistently f8 at f8 setting. > same lens is consistently f16 at f11 setting (over exaggeration). > > The meter assumes both are perfect and assigns 1/125 for > the F8 setting, 1/60 for the F11 setting. THIS IS > THE MAIN FLAW OF OPEN APERTURE METERING. It doesn't > take the real f-stop into account. > > RESULT the two exposures are not within 1/3 stop at all > settings, even though they are consistent errors. You are making a flawed assumption, and basing your premise on it. The way modern equipment works is that if it is out, it will be out by the same amount across the board, or it is defective. Calibration to within 1/10 of a stop for equipment is easily doable with modern production. My 1980s era Nikon F3 had a total system error of less than 1/10 of a stop at any aperture and shutter speed with an AI Nikkor 50mm f/1.2, and AI Nikkor 24mm f/2.8 and an AI Nikkor 200mm f/4. This was measured on a calibrated exposure tester and was repeatable over many exposure cycles. This is what modern equipment is about, and is why narrow latitude films such as Velvia can be made to work. William Robb
